Waist width? Button?

[kresty]

Not sure how to describe this area - definitely in the middle of the body below the head, so I'll call it the waist.  The upper body and lower body fit at really strange angles, but it looks like the connection isn't that difficult. 

There's a "shelf" near the top of the lower body with room for the button, and then there's a vertical wall on the hidden part of the shelf that goes up to the upper body. (I think it's vertical, you can see a bit of it in the bottom right).  I don't think this bit is beveled in the corner, so we just have a square wall with a flat flange around the bottom.

Anyhoo, I'm curious about the gap.  It is obviously wide enough for the switch, but I don't know what kind of switch it is (well it's a latching pushbutton that I presume turns on the droid or something 'cause we never see it in the up position in other photos when the droid is running).  My wild guess is that is a 10mm or 3/8" type button, which would be a little bigger for the housing.  Maybe 1/2" or so space in the gap?

(Click photo for bigger view or title to go to gallery view)

Sentry Droid power switch in off position
I think this is the power switch.  Rear of droid. Can't see it in other pix so I think it's recessed when on (like white stripe goes away) and vanishes into the black line.